Dust is everywhere, all around us, and in the air we breathe. If you wipe a finger across a shelf or a table that hasn’t been cleaned in the last few days, chances are you’ll find some dust.
Basically, dust is particulate matter made up of solid and liquid particles that come from sources such as vehicle exhaust, road dust, smokestacks, forest fires, windblown soil, volcanic emissions, and sea spray. If it is in large enough quantities that they are harmful to humans, animals or natural ecosystems, it can be classified as air pollution.
Air pollution has become a crucial global environmental problem. The adverse impact of air pollution is extensive and the detection, assessment and control of dust is a major concern for public health and safety professionals. Worldwide epidemiological studies show a consistent increase in cardiac and respiratory morbidity and mortality from exposure to dust. It is a key ingredient of polluted air and is estimated to kill more than 500,000 people each year.
Particle size, surface area, and chemical composition determine the health risk posed by dust. Dust can be classified into coarse (>2.5 gm in diameter), fine (0.1 to 2.5 gm in diameter), or ultrafine (<0.1 [micro]m in diameter) particles. The particle size of the material determines the entry pathway and where the particle will be deposited in the body and thereby what effect it will have. If the particle is small, it will penetrate deeper into the respiratory system to the lungs. Respirable materials cannot be seen with the human eye.
Concerns on air pollution issues have been raised in different industrial sectors, including demolition and construction.
One major health concern associated with dust is the presence of lead particulates in dust. Lead is a toxic substance that can affect people of any age. It is especially harmful to children, pregnant women and unborn babies. Lead accumulates in your body, so even small amounts can pose a health hazard over time.
Before 1970, paints containing high levels of lead were used in many Australian houses. Even small amounts of dust or chips of paint containing lead, generated during minor repairs, can be a health risk.
The recommended amount of lead in domestic paint has declined from 50% before 1965, to 1% in 1965 and 0.25% in 1992. In 1997 it was further reduced to 0.1%.
If you suspect that your premises may have been painted with paint containing lead and your concerned for your health, the only way to be certain is to have your paint tested by an environmental laboratory. More information is available on the Australian Government Department of the Environment and Energy website.
Many construction practices, such as drilling and grinding, and heavy vehicle trafficking of dry haul roads can produce high levels of dust. Construction and demolition activities will continue to be an important part of development therefore it is predicted that construction dust pollution will become more serious in the future.
The activities concerning soil are the most significant contributors to construction dust in the construction stage. These activities, which include earth excavation, backfilling, and transportation of soil, are ranked as the top four contributors to construction dust production.
Besides soil, there are construction materials that can easily generate dust, such as cement, concrete, lime, sands, bricks, stones, etc. Dust is usually produced in the transportation, stacking and incorrect storage of these materials.
Mitigation and minimization of dust production in the construction industry is important to minimize health risks to workers, the general public and the environment. Risk assessment and modelling data can also be useful to determine which mitigation strategies to use. Common ways to reduce dust exposure in the construction industry are by the use of (local) exhaust ventilation systems, wet dust suppression by use of (cooling) water, use of personal protective equipment or influencing worker behaviour by training and education. Based on short-term sampling, it has been shown that local exhaust ventilation and wet techniques can reduce respirable dust exposure by >90%.
Moss Environmental offers an air quality consulting and monitoring service to assist our clients develop and implement air quality management programs required by legislation to prevent air pollution. We can provide risk assessment, desktop air quality impact assessments and modelling, regulatory approvals and advice.
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- Department of the Environment and Energy. (2017). Lead in House Paint. http://www.environment.gov.au/protection/chemicals-management/lead/lead-in-house-paint access 25/10/17.